This invention relates to dipole antennas and more particularly to a low cost broadcast antenna for use in FM radio or in television broadcasting where the antennas are mounted about a support mast.
Although horizontally polarized television broadcasting has been almost exclusively used in the United States, it appears from some recent tests that circularly polarized broadcasting might well greatly improve television reception both in large metropolitan areas and fringe areas.
It is therefore desirable that a low cost horizontally polarized broadcasting antenna system be provided that is easily convertible to an antenna system that provides circularly polarized broadcasting. The antenna system must also be one which when mounted to conventional support masts, radiates signals in an omnidirectional pattern about the mast such that when this mast is erected in the center of a city, for example, substantially equal coverage is provided about the city. Although crossed dipole antenna systems are well known as exemplified by U.S. Pat. Nos. 3,896,450; 3,725,943 and 3,922,683, these antennas comprise complex support and feed structures and further are not easily convertible from linear to circular polarization.